Capacitors and other electronic elements within the VSD (Variable Speed Drive) apparatus generate heat. If the heat cannot be emitted effectively, it will result in a rise in the temperature of the capacitors and other electronic elements, even failure of the apparatus. For this reason, there is a need for a cooling structure to direct cool air going through the heated elements, emitting the heat out of the apparatus. Generally, the cooling fan provided in a conventional VSD apparatus is provided at a first end, can rotate in only one direction, and direct cool air flow from a second end that is opposite to the first end to the first end. Since the temperature of the cool air starts to rise at the second end, cooling effect on the capacitors at the first end is reduced when the cool air reaches the first end. As a result, in terms of the whole array of capacitors, as the capacitors continue to operate, the capacitor at the first end gets increasing warmer compared to the capacitor at the second end. Due to inadequate cooling for the capacitor at the first end, the life span decreases, even to the extent that the apparatus fails. Therefore, there is a need for a cooling structure that is capable to adequately cool down the capacitors at both ends of the array of capacitors.